Add functionality to generate a schema from a values.yaml

Signed-off-by: Ian Howell <ian.howell0@gmail.com>

pkg/chartutil/values.go

@@ -203,6 +203,73 @@ func ReadSchematizedValues(data, schemaData []byte) (Values, error) {
 	return values, nil
 }
 
+// GenerateSchema will create a JSON Schema (in YAML format) for the given values
+func GenerateSchema(values Values) Schema {
+	schema := Schema{
+		"type":  "object",
+		"title": "Values",
+	}
+	if len(values) > 0 {
+		schema["properties"] = parsePropertiesFromValues(values)
+	}
+	return schema
+}
+
+func parsePropertiesFromValues(values Values) map[string]map[string]interface{} {
+	properties := make(map[string]map[string]interface{})
+	for k, v := range values {
+		// If the value is null, then there's no way to determine the properties attributes
+		if v == nil || v == "" {
+			continue
+		}
+
+		properties[k] = make(map[string]interface{})
+		// the following types are the only types possible from unmarshalling
+		switch v.(type) {
+		case bool:
+			properties[k]["type"] = "bool"
+		case float64:
+			properties[k]["type"] = "number"
+		case string:
+			properties[k]["type"] = "string"
+		case []interface{}:
+			properties[k]["type"] = "array"
+			properties[k]["items"] = parseItemsFromValues(v.([]interface{}))
+		case map[string]interface{}:
+			properties[k]["type"] = "object"
+			object := parsePropertiesFromValues(v.(map[string]interface{}))
+			if len(object) > 0 {
+				properties[k]["object"] = object
+			}
+		}
+	}
+	return properties
+}
+
+func parseItemsFromValues(items []interface{}) map[string]interface{} {
+	properties := make(map[string]interface{})
+	v := items[0]
+	// the following types are the only types possible from unmarshalling
+	switch v.(type) {
+	case bool:
+		properties["type"] = "bool"
+	case float64:
+		properties["type"] = "number"
+	case string:
+		properties["type"] = "string"
+	case []interface{}:
+		properties["type"] = "array"
+		properties["items"] = parseItemsFromValues(v.([]interface{}))
+	case map[string]interface{}:
+		properties["type"] = "object"
+		object := parsePropertiesFromValues(v.(map[string]interface{}))
+		if len(object) > 0 {
+			properties["object"] = object
+		}
+	}
+	return properties
+}
+
 // CoalesceValues coalesces all of the values in a chart (and its subcharts).
 //
 // Values are coalesced together using the following rules:

pkg/chartutil/values_test.go

@@ -435,6 +435,7 @@ func TestCoalesceTables(t *testing.T) {
 		t.Errorf("Expected boat string, got %v", dst["boat"])
 	}
 }
+
 func TestPathValue(t *testing.T) {
 	doc := `
 title: "Moby Dick"
@@ -627,6 +628,48 @@ func matchSchema(t *testing.T, data Schema) {
 	assertEqualProperty(t, property, expected, data)
 }
 
+func TestGenerateSchema(t *testing.T) {
+	doc := `# Test YAML parse
+firstname: John
+middlename: null
+lastname: Doe
+age: 25
+likesCoffee: true
+employmentInfo:
+  title: Software Developer
+  salary: 100000
+addresses:
+  - city: Springfield
+    street: Main
+    number: 12345
+  - city: New York
+    street: Broadway
+    number: 67890
+phoneNumbers:
+  - "(888) 888-8888"
+  - "(555) 555-5555"
+`
+
+	values, _ := ReadValues([]byte(doc))
+	schema := GenerateSchema(values)
+	assertEqualProperty(t, ".title", "Values", schema)
+	assertEqualProperty(t, ".type", "object", schema)
+	assertEqualProperty(t, ".properties.firstname.type", "string", schema)
+	assertEqualProperty(t, ".properties.lastname.type", "string", schema)
+	assertEqualProperty(t, ".properties.age.type", "number", schema)
+	assertEqualProperty(t, ".properties.likesCoffee.type", "bool", schema)
+	assertEqualProperty(t, ".properties.employmentInfo.type", "object", schema)
+	assertEqualProperty(t, ".properties.employmentInfo.object.title.type", "string", schema)
+	assertEqualProperty(t, ".properties.employmentInfo.object.salary.type", "number", schema)
+	assertEqualProperty(t, ".properties.addresses.type", "array", schema)
+	assertEqualProperty(t, ".properties.addresses.items.type", "object", schema)
+	assertEqualProperty(t, ".properties.addresses.items.object.street.type", "string", schema)
+	assertEqualProperty(t, ".properties.addresses.items.object.number.type", "number", schema)
+	assertEqualProperty(t, ".properties.addresses.items.object.city.type", "string", schema)
+	assertEqualProperty(t, ".properties.phoneNumbers.type", "array", schema)
+	assertEqualProperty(t, ".properties.phoneNumbers.items.type", "string", schema)
+}
+
 func assertEqualProperty(t *testing.T, property, expected string, data map[string]interface{}) {
 	if o, err := ttpl("{{"+property+"}}", data); err != nil {
 		t.Errorf("%s: %s", property, err)